Please name a couple that are ready to be brought up and do just that, without hurting their development.

Jordan Danks is already on the MLB roster and we see what he is capable of doing. There is not one player that comes to mind that can be brought up and help this team win now.

I'll admit I don't really know our minor leagues too well anymore. And, there probably is no one down there to help us "win now." But, this team isn't just one player away from being good. I just meant that there's surely somebody there that can outhit .160. I'll also admit you have a point about development though, because a replacement would have to either DH or play 1B. You have unlimited options of putting any minor league hitter in the DH role, but then you would take time away from them playing the field. However, you could even throw Dwayne Wise in the DH role for the rest of the season and he'd surely hit over .200.
Bottom line, this team's not going to win with replacing one player.